Method and apparatus for mobility handling in wireless communication system

ABSTRACT

The present disclosure relates to a mobility handling in wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device comprises: identifying a first cell which satisfies a mobility condition for the first cell included in a conditional mobility command of the first cell; and based on a determination that a target cell configuration for the first cell is unavailable, transmitting a report comprising information for an unavailability of the target cell configuration for the first cell.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119 (a), this application claims the benefit ofearlier filing date and right of priority to Korean Patent ApplicationNo. 10-2019-0127104, filed on Oct. 14, 2019, the contents of which areall hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to a mobility handling in wirelesscommunications.

Related Art

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPPto develop requirements and specifications for new radio (NR) systems.3GPP has to identify and develop the technology components needed forsuccessfully standardizing the new RAT timely satisfying both the urgentmarket needs, and the more long-term requirements set forth by the ITUradio communication sector (ITU-R) international mobiletelecommunications (IMT)-2020 process. Further, the NR should be able touse any spectrum band ranging at least up to 100 GHz that may be madeavailable for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usagescenarios, requirements and deployment scenarios including enhancedmobile broadband (eMBB), massive machine-type-communications (mMTC),ultra-reliable and low latency communications (URLLC), etc. The NR shallbe inherently forward compatible.

In a wireless communication system, a wireless device and/or userequipment (UE) may move along cells/base stations deployed in a widerange of areas. If a serving cell quality degrades as the wirelessdevice moves far away from the serving cell, the wireless device mayperform a mobility from the serving cell to another cell. The mobilityshould be properly handled before and during a mobility procedure, andeven after the mobility procedure.

SUMMARY OF THE DISCLOSURE Technical Problem

An aspect of the present disclosure is to provide method and apparatusfor a mobility handling in a wireless communication system.

Another aspect of the present disclosure is to provide method andapparatus for a mobility handling after completing a mobility procedurein a wireless communication system.

Another aspect of the present disclosure is to provide method andapparatus for handling an invalid scenario after performing aconditional mobility in a wireless communication system.

Another aspect of the present disclosure is to provide method andapparatus for preventing unnecessary actions after performing aconditional mobility in a wireless communication system.

Technical Solution

According to an embodiment of the present disclosure, a method performedby a wireless device comprises: identifying a first cell which satisfiesa mobility condition for the first cell included in a conditionalmobility command of the first cell; and based on a determination that atarget cell configuration for the first cell is unavailable,transmitting a report comprising information for an unavailability ofthe target cell configuration for the first cell.

According to an embodiment of the present disclosure, a wireless devicein a wireless communication system comprises: a transceiver; a memory;and at least one processor operatively coupled to the transceiver andthe memory, and configured to: identify a first cell which satisfies amobility condition for the first cell included in a conditional mobilitycommand of the first cell, and based on a determination that a targetcell configuration for the first cell is unavailable, control thetransceiver to transmit a report comprising information for anunavailability of the target cell configuration for the first cell.

According to an embodiment of the present disclosure, acomputer-readable medium having recorded thereon a program forperforming each step of a method on a computer is provided. The methodcomprises: identifying a first cell which satisfies a mobility conditionfor the first cell included in a conditional mobility command of thefirst cell; and based on a determination that a target cellconfiguration for the first cell is unavailable, transmitting a reportcomprising information for an unavailability of the target cellconfiguration for the first cell.

Advantageous Effect

The present disclosure can have various advantageous effects.

For example, the present disclosure resolves to prevent unnecessaryinvalid handling when a mobility condition for a candidate target cellis met without the corresponding target cell configuration aftersuccessful mobility such as CHO. Also, the UE doesn't have to performRRC re-establishment procedure which cause data interruption by invalidcase handling.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

FIG. 5 shows a block diagram of a user plane protocol stack to which thetechnical features of the present disclosure can be applied.

FIG. 6 shows a block diagram of a control plane protocol stack to whichthe technical features of the present disclosure can be applied.

FIG. 7 illustrates a frame structure in a 3GPP based wirelesscommunication system.

FIG. 8 illustrates a data flow example in the 3GPP NR system.

FIG. 9 shows an example of a method for a measurement and reporting towhich technical features of the present disclosure can be applied.

FIG. 10 shows an example of a conditional mobility procedure to whichtechnical features of the present disclosure can be applied.

FIGS. 11A, 11B and 11C show an example of a measurement ID swapping towhich technical features of the present disclosure can be applied.

FIG. 12 shows an example of a method for handling a conditional mobilitycommand after performing a conditional mobility according to anembodiment of the present disclosure.

FIG. 13 shows an example of a method for a CHO command handling aftercompleting a CHO according to an embodiment of the present disclosure.

FIG. 14 shows a UE to implement an embodiment of the present disclosure.The present disclosure described above for UE side may be applied tothis embodiment.

FIG. 15 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

FIG. 16 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

FIG. 17 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The technical features described below may be used by a communicationstandard by the 3rd generation partnership project (3GPP)standardization organization, a communication standard by the instituteof electrical and electronics engineers (IEEE), etc. For example, thecommunication standards by the 3GPP standardization organization includelong-term evolution (LTE) and/or evolution of LTE systems. The evolutionof LTE systems includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G newradio (NR). The communication standard by the IEEE standardizationorganization includes a wireless local area network (WLAN) system suchas IEEE 802.11a/b/g/n/ac/ax. The above system uses various multipleaccess technologies such as orthogonal frequency division multipleaccess (OFDMA) and/or single carrier frequency division multiple access(SC-FDMA) for downlink (DL) and/or uplink (UL). For example, only OFDMAmay be used for DL and only SC-FDMA may be used for UL. Alternatively,OFDMA and SC-FDMA may be used for DL and/or UL.

In the present disclosure, “A or B” may mean “only A”, “only B”, or“both A and B”. In other words, “A or B” in the present disclosure maybe interpreted as “A and/or B”. For example, “A, B or C” in the presentdisclosure may mean “only A”, “only B”, “only C”, or “any combination ofA, B and C”.

In the present disclosure, slash (/) or comma (,) may mean “and/or”. Forexample, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “onlyA”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, Bor C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B” or “both A and B”. In addition, the expression “at least one ofA or B” or “at least one of A and/or B” in the present disclosure may beinterpreted as same as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B and C” maymean “only A”, “only B”, “only C”, or “any combination of A, B and C”.In addition, “at least one of A, B or C” or “at least one of A, B and/orC” may mean “at least one of A, B and C”.

Also, parentheses used in the present disclosure may mean “for example”.In detail, when it is shown as “control information (PDCCH)”, “PDCCH”may be proposed as an example of “control information”. In other words,“control information” in the present disclosure is not limited to“PDCCH”, and “PDDCH” may be proposed as an example of “controlinformation”. In addition, even when shown as “control information(i.e., PDCCH)”, “PDCCH” may be proposed as an example of “controlinformation”.

Technical features that are separately described in one drawing in thepresent disclosure may be implemented separately or simultaneously.

The terms used throughout the disclosure can be defined as thefollowings:

‘Mobility’ refers to a procedure for i)changing a PCell of a UE (i.e.,handover or PCell change), ii)changing a PSCell of a UE (i.e., SN changeor PSCell change), and/or iii)adding a PSCell for a UE (i.e., SNaddition or PSCell addition). Therefore, the mobility may comprise atleast one of a handover, an SN change or an SN addition. In other words,the mobility may comprise at least one of PCell change, PSCell change orPSCell addition. Throughout the disclosure, performing a mobility to atarget cell may refer to applying a mobility command of the target cellor applying a target cell configuration for the target cell in themobility command of the target cell. The target cell configuration forthe target cell may comprise RRC reconfiguration parameters associatedwith the mobility to the target cell. Further, RRC reconfiguration andRRC connection reconfiguration may be used interchangeably.

‘SN mobility’ refers to a procedure for i)changing a PSCell of a UE(i.e., SN change or PSCell change), and/or ii)adding a PSCell for a UE(i.e., SN addition or PSCell addition). Therefore, the SN mobility maycomprise at least one of an SN change or an SN addition. In other words,the SN mobility may comprise at least one of PSCell change or PSCelladdition. Throughout the disclosure, performing an SN mobility to atarget cell may refer to applying an SN mobility command of the targetcell or applying a target cell configuration for the target cell in theSN mobility command of the target cell. The target cell configurationfor the target cell may comprise RRC reconfiguration parametersassociated with the SN mobility to the target cell. The SN mobility maybe a kind of a mobility. The SN mobility command may comprise a SNchange command for performing SN change, or SN addition command forperforming SN addition.

‘Mobility condition for a target cell’ refers to a triggering conditionfor a mobility to the target cell. That is, the mobility condition for atarget cell refers to a condition that should be satisfied fortriggering a mobility to the target cell. Mobility condition maycomprise at least one of an event, time-to-trigger (TTT), offset value,or threshold value(s). The mobility condition for an event may besatisfied if an entering condition for the event is satisfied for atleast the TTT. For example, the entering condition for event A3 may besatisfied if a signal quality for a target cell is better than that fora source cell more than or equal to the offset value. For anotherexample, the entering condition for event A5 may be satisfied if asignal quality for a target cell is better than a first threshold and asignal quality for a source cell is lower than a second threshold.

‘SN mobility condition for a target cell’ refers to a triggeringcondition for an SN mobility (i.e., SN addition or SN change) to thetarget cell. That is, the SN mobility condition for a target cell refersto a condition that should be satisfied for triggering an SN mobility tothe target cell. SN mobility condition for a target cell may beclassified as:

i) SN addition condition for a target cell, which refers to a triggeringcondition for an SN addition of the target cell; or

ii) SN change condition for a target cell, which refers to a triggeringcondition for an SN change to the target cell.

SN mobility condition may comprise at least one of an event,time-to-trigger (TTT), offset value, or threshold value(s). The SNmobility condition for an event may be satisfied if an enteringcondition for the event is satisfied for at least the TTT.

For example, SN addition condition may be related to event A4 or eventB1. The entering condition for event A4 or B1 may be satisfied if asignal quality for a target cell is better than a threshold.

For example, SN change condition may be related to event A3 or event A5.The entering condition for event A3 may be satisfied if a signal qualityfor a target cell is better than that for a source PScell more than orequal to the offset value. For another example, the entering conditionfor event A5 may be satisfied if a signal quality for a target cell isbetter than a first threshold and a signal quality for a source PScellis lower than a second threshold.

‘Conditional mobility’ refers to a mobility that is performed to atarget cell which satisfies a triggering condition among a plurality ofcandidate target cells. Throughout the disclosure, performing aconditional mobility to a target cell may refer to applying aconditional mobility command of a target cell which satisfies a mobilitycondition for the target cell among a plurality of candidate targetcells or applying a target cell configuration for the target cell in theconditional mobility command of the target cell which satisfies amobility condition for the target cell among the plurality of candidatetarget cells. The target cell configuration for the target cell maycomprise RRC reconfiguration parameters associated with the conditionalmobility to the target cell.

Throughout the disclosure, the terms ‘radio access network (RAN) node’,‘base station’, ‘eNB’, ‘gNB’ and ‘cell’ may be used interchangeably.Further, a UE may be a kind of a wireless device, and throughout thedisclosure, the terms ‘UE’ and ‘wireless device’ may be usedinterchangeably.

Throughout the disclosure, the terms ‘cell quality’, ‘signal strength’,‘signal quality’, ‘channel state’, ‘channel quality’, ‘ channelstate/reference signal received power (RSRP)’ and ‘ reference signalreceived quality (RSRQ)’ may be used interchangeably.

The following drawings are created to explain specific embodiments ofthe present disclosure. The names of the specific devices or the namesof the specific signals/messages/fields shown in the drawings areprovided by way of example, and thus the technical features of thepresent disclosure are not limited to the specific names used in thefollowing drawings.

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

The 5G usage scenarios shown in FIG. 1 are only exemplary, and thetechnical features of the present disclosure can be applied to other 5Gusage scenarios which are not shown in FIG. 1.

Referring to FIG. 1, the three main requirements areas of 5G include (1)enhanced mobile broadband (eMBB) domain, (2) massive machine typecommunication (mMTC) area, and (3) ultra-reliable and low latencycommunications (URLLC) area. Some use cases may require multiple areasfor optimization and, other use cases may only focus on only one keyperformance indicator (KPI). 5G is to support these various use cases ina flexible and reliable way.

eMBB focuses on across-the-board enhancements to the data rate, latency,user density, capacity and coverage of mobile broadband access. The eMBBaims ˜10 Gbps of throughput. eMBB far surpasses basic mobile Internetaccess and covers rich interactive work and media and entertainmentapplications in cloud and/or augmented reality. Data is one of the keydrivers of 5G and may not be able to see dedicated voice services forthe first time in the 5G era. In 5G, the voice is expected to beprocessed as an application simply using the data connection provided bythe communication system. The main reason for the increased volume oftraffic is an increase in the size of the content and an increase in thenumber of applications requiring high data rates. Streaming services(audio and video), interactive video and mobile Internet connectivitywill become more common as more devices connect to the Internet. Many ofthese applications require always-on connectivity to push real-timeinformation and notifications to the user. Cloud storage andapplications are growing rapidly in mobile communication platforms,which can be applied to both work and entertainment. Cloud storage is aspecial use case that drives growth of uplink data rate. 5G is also usedfor remote tasks on the cloud and requires much lower end-to-end delayto maintain a good user experience when the tactile interface is used.In entertainment, for example, cloud games and video streaming areanother key factor that increases the demand for mobile broadbandcapabilities. Entertainment is essential in smartphones and tabletsanywhere, including high mobility environments such as trains, cars andairplanes. Another use case is augmented reality and informationretrieval for entertainment. Here, augmented reality requires very lowlatency and instantaneous data amount.

mMTC is designed to enable communication between devices that arelow-cost, massive in number and battery-driven, intended to supportapplications such as smart metering, logistics, and field and bodysensors. mMTC aims ˜10 years on battery and/or ˜1 million devices/km2.mMTC allows seamless integration of embedded sensors in all areas and isone of the most widely used 5G applications. Potentially by 2020,internet-of-things (IoT) devices are expected to reach 20.4 billion.Industrial IoT is one of the areas where 5G plays a key role in enablingsmart cities, asset tracking, smart utilities, agriculture and securityinfrastructures.

URLLC will make it possible for devices and machines to communicate withultra-reliability, very low latency and high availability, making itideal for vehicular communication, industrial control, factoryautomation, remote surgery, smart grids and public safety applications.URLLC aims ˜1 ms of latency. URLLC includes new services that willchange the industry through links with ultra-reliability/low latency,such as remote control of key infrastructure and self-driving vehicles.The level of reliability and latency is essential for smart gridcontrol, industrial automation, robotics, drones control andcoordination.

Next, a plurality of use cases included in the triangle of FIG. 1 willbe described in more detail.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as a means of delivering streams rated from hundreds of megabitsper second to gigabits per second. This high speed can be required todeliver TVs with resolutions of 4K or more (6K, 8K and above) as well asvirtual reality (VR) and augmented reality (AR). VR and AR applicationsinclude mostly immersive sporting events. Certain applications mayrequire special network settings. For example, in the case of a VR game,a game company may need to integrate a core server with an edge networkserver of a network operator to minimize delay.

Automotive is expected to become an important new driver for 5G, withmany use cases for mobile communications to vehicles. For example,entertainment for passengers demands high capacity and high mobilebroadband at the same time. This is because future users will continueto expect high-quality connections regardless of their location andspeed. Another use case in the automotive sector is an augmented realitydashboard. The driver can identify an object in the dark on top of whatis being viewed through the front window through the augmented realitydashboard. The augmented reality dashboard displays information thatwill inform the driver about the object's distance and movement. In thefuture, the wireless module enables communication between vehicles,information exchange between the vehicle and the supportinginfrastructure, and information exchange between the vehicle and otherconnected devices (e.g. devices accompanied by a pedestrian). The safetysystem allows the driver to guide the alternative course of action sothat he can drive more safely, thereby reducing the risk of accidents.The next step will be a remotely controlled vehicle or self-drivingvehicle. This requires a very reliable and very fast communicationbetween different self-driving vehicles and between vehicles andinfrastructure. In the future, a self-driving vehicle will perform alldriving activities, and the driver will focus only on traffic that thevehicle itself cannot identify. The technical requirements ofself-driving vehicles require ultra-low latency and high-speedreliability to increase traffic safety to a level not achievable byhumans.

Smart cities and smart homes, which are referred to as smart societies,will be embedded in high density wireless sensor networks. Thedistributed network of intelligent sensors will identify conditions forcost and energy-efficient maintenance of a city or house. A similarsetting can be performed for each home. Temperature sensors, windows andheating controllers, burglar alarms and appliances are all wirelesslyconnected. Many of these sensors typically require low data rate, lowpower and low cost. However, for example, real-time high-definition (HD)video may be required for certain types of devices for monitoring.

The consumption and distribution of energy, including heat or gas, ishighly dispersed, requiring automated control of distributed sensornetworks. The smart grid interconnects these sensors using digitalinformation and communication technologies to collect and act oninformation. This information can include supplier and consumerbehavior, allowing the smart grid to improve the distribution of fuel,such as electricity, in terms of efficiency, reliability, economy,production sustainability, and automated methods. The smart grid can beviewed as another sensor network with low latency.

The health sector has many applications that can benefit from mobilecommunications. Communication systems can support telemedicine toprovide clinical care in remote locations. This can help to reducebarriers to distance and improve access to health services that are notcontinuously available in distant rural areas. It is also used to savelives in critical care and emergency situations. Mobile communicationbased wireless sensor networks can provide remote monitoring and sensorsfor parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantin industrial applications. Wiring costs are high for installation andmaintenance. Thus, the possibility of replacing a cable with a wirelesslink that can be reconfigured is an attractive opportunity in manyindustries. However, achieving this requires that wireless connectionsoperate with similar delay, reliability, and capacity as cables and thattheir management is simplified. Low latency and very low errorprobabilities are new requirements that need to be connected to 5G.

Logistics and freight tracking are important use cases of mobilecommunications that enable tracking of inventory and packages anywhereusing location based information systems. Use cases of logistics andfreight tracking typically require low data rates, but require a largerange and reliable location information.

NR supports multiple numerology (or, subcarrier spacing (SCS)) tosupport various 5G services. For example, when the SCS is 15 kHz, widearea in traditional cellular bands may be supported. When the SCS is 30kHz/60 kHz, dense-urban, lower latency and wider carrier bandwidth maybe supported. When the SCS is 60 kHz or higher, a bandwidth greater than24.25 GHz may be supported to overcome phase noise.

The NR frequency band may be defined as two types of frequency range,i.e., FR1 and FR2. The numerical value of the frequency range may bechanged. For example, the frequency ranges of the two types (FR1 andFR2) may be as shown in Table 1 below. For ease of explanation, in thefrequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”,FR2 may mean “above 6 GHz range,” and may be referred to as millimeterwave (mmW).

TABLE 1 Frequency Range Corresponding frequency designation rangeSubcarrier Spacing FR1  450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NRsystem may be changed. For example, FR1 may include a frequency band of410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may includea frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. Forexample, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) ormore included in FR1 may include an unlicensed band. Unlicensed bandsmay be used for a variety of purposes, for example for communication forvehicles (e.g., autonomous driving).

TABLE 2 Frequency Range Corresponding frequency designation rangeSubcarrier Spacing FR1  410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

Referring to FIG. 2, the wireless communication system may include afirst device 210 and a second device 220.

The first device 210 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, an unmanned aerial vehicle(UAV), an artificial intelligence (AI) module, a robot, an AR device, aVR device, a mixed reality (MR) device, a hologram device, a publicsafety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

The second device 220 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, a UAV, an AI module, arobot, an AR device, a VR device, an MR device, a hologram device, apublic safety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

For example, the UE may include a mobile phone, a smart phone, a laptopcomputer, a digital broadcasting terminal, a personal digital assistant(PDA), a portable multimedia player (PMP), a navigation device, a slatepersonal computer (PC), a tablet PC, an ultrabook, a wearable device(e.g. a smartwatch, a smart glass, a head mounted display (HMD)). Forexample, the HMD may be a display device worn on the head. For example,the HMD may be used to implement AR, VR and/or MR.

For example, the drone may be a flying object that is flying by a radiocontrol signal without a person boarding it. For example, the VR devicemay include a device that implements an object or background in thevirtual world. For example, the AR device may include a device thatimplements connection of an object and/or a background of a virtualworld to an object and/or a background of the real world. For example,the MR device may include a device that implements fusion of an objectand/or a background of a virtual world to an object and/or a backgroundof the real world. For example, the hologram device may include a devicethat implements a 360-degree stereoscopic image by recording and playingstereoscopic information by utilizing a phenomenon of interference oflight generated by the two laser lights meeting with each other, calledholography. For example, the public safety device may include a videorelay device or a video device that can be worn by the user's body. Forexample, the MTC device and the IoT device may be a device that do notrequire direct human intervention or manipulation. For example, the MTCdevice and the IoT device may include a smart meter, a vending machine,a thermometer, a smart bulb, a door lock and/or various sensors. Forexample, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, handling, or preventing a disease.For example, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, or correcting an injury or disorder.For example, the medical device may be a device used for the purpose ofinspecting, replacing or modifying a structure or function. For example,the medical device may be a device used for the purpose of controllingpregnancy. For example, the medical device may include a treatmentdevice, a surgical device, an (in vitro) diagnostic device, a hearingaid and/or a procedural device, etc. For example, a security device maybe a device installed to prevent the risk that may occur and to maintainsafety. For example, the security device may include a camera, aclosed-circuit TV (CCTV), a recorder, or a black box. For example, thefin-tech device may be a device capable of providing financial servicessuch as mobile payment. For example, the fin-tech device may include apayment device or a point of sales (POS). For example, theclimate/environmental device may include a device for monitoring orpredicting the climate/environment.

The first device 210 may include at least one or more processors, suchas a processor 211, at least one memory, such as a memory 212, and atleast one transceiver, such as a transceiver 213. The processor 211 mayperform the functions, procedures, and/or methods of the first devicedescribed throughout the disclosure. The processor 211 may perform oneor more protocols. For example, the processor 211 may perform one ormore layers of the air interface protocol. The memory 212 is connectedto the processor 211 and may store various types of information and/orinstructions. The transceiver 213 is connected to the processor 211 andmay be controlled by the processor 211 to transmit and receive wirelesssignals.

The second device 220 may include at least one or more processors, suchas a processor 221, at least one memory, such as a memory 222, and atleast one transceiver, such as a transceiver 223. The processor 221 mayperform the functions, procedures, and/or methods of the second device220 described throughout the disclosure. The processor 221 may performone or more protocols. For example, the processor 221 may perform one ormore layers of the air interface protocol. The memory 222 is connectedto the processor 221 and may store various types of information and/orinstructions. The transceiver 223 is connected to the processor 221 andmay be controlled by the processor 221 to transmit and receive wirelesssignals.

The memory 212, 222 may be connected internally or externally to theprocessor 211, 212, or may be connected to other processors via avariety of technologies such as wired or wireless connections.

The first device 210 and/or the second device 220 may have more than oneantenna. For example, antenna 214 and/or antenna 224 may be configuredto transmit and receive wireless signals.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

Specifically, FIG. 3 shows a system architecture based on anevolved-UMTS terrestrial radio access network (E-UTRAN). Theaforementioned LTE is a part of an evolved-UTMS (e-UMTS) using theE-UTRAN.

Referring to FIG. 3, the wireless communication system includes one ormore user equipment (UE) 310, an E-UTRAN and an evolved packet core(EPC). The UE 310 refers to a communication equipment carried by a user.The UE 310 may be fixed or mobile. The UE 310 may be referred to asanother terminology, such as a mobile station (MS), a user terminal(UT), a subscriber station (SS), a wireless device, etc.

The E-UTRAN consists of one or more evolved NodeB (eNB) 320. The eNB 320provides the E-UTRA user plane and control plane protocol terminationstowards the UE 10. The eNB 320 is generally a fixed station thatcommunicates with the UE 310. The eNB 320 hosts the functions, such asinter-cell radio resource management (RRM), radio bearer (RB) control,connection mobility control, radio admission control, measurementconfiguration/provision, dynamic resource allocation (scheduler), etc.The eNB 320 may be referred to as another terminology, such as a basestation (BS), a base transceiver system (BTS), an access point (AP),etc.

A downlink (DL) denotes communication from the eNB 320 to the UE 310. Anuplink (UL) denotes communication from the UE 310 to the eNB 320. Asidelink (SL) denotes communication between the UEs 310. In the DL, atransmitter may be a part of the eNB 320, and a receiver may be a partof the UE 310. In the UL, the transmitter may be a part of the UE 310,and the receiver may be a part of the eNB 320. In the SL, thetransmitter and receiver may be a part of the UE 310.

The EPC includes a mobility management entity (MME), a serving gateway(S-GW) and a packet data network (PDN) gateway (P-GW). The MME hosts thefunctions, such as non-access stratum (NAS) security, idle statemobility handling, evolved packet system (EPS) bearer control, etc. TheS-GW hosts the functions, such as mobility anchoring, etc. The S-GW is agateway having an E-UTRAN as an endpoint. For convenience, MME/S-GW 330will be referred to herein simply as a “gateway,” but it is understoodthat this entity includes both the MME and S-GW. The P-GW hosts thefunctions, such as UE Internet protocol (IP) address allocation, packetfiltering, etc. The P-GW is a gateway having a PDN as an endpoint. TheP-GW is connected to an external network.

The UE 310 is connected to the eNB 320 by means of the Uu interface. TheUEs 310 are interconnected with each other by means of the PC5interface. The eNBs 320 are interconnected with each other by means ofthe X2 interface. The eNBs 320 are also connected by means of the S1interface to the EPC, more specifically to the MME by means of theS1-MME interface and to the S-GW by means of the S1-U interface. The Siinterface supports a many-to-many relation between MMEs/S-GWs and eNBs.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

Specifically, FIG. 4 shows a system architecture based on a 5G NR. Theentity used in the 5G NR (hereinafter, simply referred to as “NW”) mayabsorb some or all of the functions of the entities introduced in FIG. 3(e.g. eNB, MME, S-GW). The entity used in the NR may be identified bythe name “NG” for distinction from the LTE/LTE-A.

Referring to FIG. 4, the wireless communication system includes one ormore UE 410, a next-generation RAN (NG-RAN) and a 5th generation corenetwork (5GC). The NG-RAN consists of at least one NG-RAN node. TheNG-RAN node is an entity corresponding to the eNB 320 shown in FIG. 3.The NG-RAN node consists of at least one gNB 421 and/or at least oneng-eNB 422. The gNB 421 provides NR user plane and control planeprotocol terminations towards the UE 410. The ng-eNB 422 provides E-UTRAuser plane and control plane protocol terminations towards the UE 410.

The 5GC includes an access and mobility management function (AMF), auser plane function (UPF) and a session management function (SMF). TheAMF hosts the functions, such as NAS security, idle state mobilityhandling, etc. The AMF is an entity including the functions of theconventional MME. The UPF hosts the functions, such as mobilityanchoring, protocol data unit (PDU) handling. The UPF an entityincluding the functions of the conventional S-GW. The SMF hosts thefunctions, such as UE IP address allocation, PDU session control.

The gNBs 421 and ng-eNBs 422 are interconnected with each other by meansof the Xn interface. The gNBs 421 and ng-eNBs 422 are also connected bymeans of the NG interfaces to the 5GC, more specifically to the AMF bymeans of the NG-C interface and to the UPF by means of the NG-Uinterface.

A protocol structure between network entities described above isdescribed. On the system of FIG. 3 and/or FIG. 4, layers of a radiointerface protocol between the UE and the network (e.g. NG-RAN and/orE-UTRAN) may be classified into a first layer (L1), a second layer (L2),and a third layer (L3) based on the lower three layers of the opensystem interconnection (OSI) model that is well-known in thecommunication system.

FIG. 5 shows a block diagram of a user plane protocol stack to which thetechnical features of the present disclosure can be applied. FIG. 6shows a block diagram of a control plane protocol stack to which thetechnical features of the present disclosure can be applied.

The user/control plane protocol stacks shown in FIG. 5 and FIG. 6 areused in NR. However, user/control plane protocol stacks shown in FIG. 5and FIG. 6 may be used in LTE/LTE-A without loss of generality, byreplacing gNB/AMF with eNB/MME.

Referring to FIG. 5 and FIG. 6, a physical (PHY) layer belonging to L1.The PHY layer offers information transfer services to media accesscontrol (MAC) sublayer and higher layers. The PHY layer offers to theMAC sublayer transport channels. Data between the MAC sublayer and thePHY layer is transferred via the transport channels. Between differentPHY layers, i.e., between a PHY layer of a transmission side and a PHYlayer of a reception side, data is transferred via the physicalchannels.

The MAC sublayer belongs to L2. The main services and functions of theMAC sublayer include mapping between logical channels and transportchannels, multiplexing/de-multiplexing of MAC service data units (SDUs)belonging to one or different logical channels into/from transportblocks (TB) delivered to/from the physical layer on transport channels,scheduling information reporting, error correction through hybridautomatic repeat request (HARQ), priority handling between UEs by meansof dynamic scheduling, priority handling between logical channels of oneUE by means of logical channel prioritization (LCP), etc. The MACsublayer offers to the radio link control (RLC) sublayer logicalchannels.

The RLC sublayer belong to L2. The RLC sublayer supports threetransmission modes, i.e. transparent mode (TM), unacknowledged mode(UM), and acknowledged mode (AM), in order to guarantee various qualityof services (QoS) required by radio bearers. The main services andfunctions of the RLC sublayer depend on the transmission mode. Forexample, the RLC sublayer provides transfer of upper layer PDUs for allthree modes, but provides error correction through ARQ for AM only. InLTE/LTE-A, the RLC sublayer provides concatenation, segmentation andreassembly of RLC SDUs (only for UM and AM data transfer) andre-segmentation of RLC data PDUs (only for AM data transfer). In NR, theRLC sublayer provides segmentation (only for AM and UM) andre-segmentation (only for AM) of RLC SDUs and reassembly of SDU (onlyfor AM and UM). That is, the NR does not support concatenation of RLCSDUs. The RLC sublayer offers to the packet data convergence protocol(PDCP) sublayer RLC channels.

The PDCP sublayer belong to L2. The main services and functions of thePDCP sublayer for the user plane include header compression anddecompression, transfer of user data, duplicate detection, PDCP PDUrouting, retransmission of PDCP SDUs, ciphering and deciphering, etc.The main services and functions of the PDCP sublayer for the controlplane include ciphering and integrity protection, transfer of controlplane data, etc.

The service data adaptation protocol (SDAP) sublayer belong to L2. TheSDAP sublayer is only defined in the user plane. The SDAP sublayer isonly defined for NR. The main services and functions of SDAP include,mapping between a QoS flow and a data radio bearer (DRB), and markingQoS flow ID (QFI) in both DL and UL packets. The SDAP sublayer offers to5GC QoS flows.

A radio resource control (RRC) layer belongs to L3. The RRC layer isonly defined in the control plane. The RRC layer controls radioresources between the UE and the network. To this end, the RRC layerexchanges RRC messages between the UE and the BS. The main services andfunctions of the RRC layer include broadcast of system informationrelated to AS and NAS, paging, establishment, maintenance and release ofan RRC connection between the UE and the network, security functionsincluding key management, establishment, configuration, maintenance andrelease of radio bearers, mobility functions, QoS management functions,UE measurement reporting and control of the reporting, NAS messagetransfer to/from NAS from/to UE.

In other words, the RRC layer controls logical channels, transportchannels, and physical channels in relation to the configuration,reconfiguration, and release of radio bearers. A radio bearer refers toa logical path provided by L1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAPsublayer) for data transmission between a UE and a network. Setting theradio bearer means defining the characteristics of the radio protocollayer and the channel for providing a specific service, and setting eachspecific parameter and operation method. Radio bearer may be dividedinto signaling RB (SRB) and data RB (DRB). The SRB is used as a path fortransmitting RRC messages in the control plane, and the DRB is used as apath for transmitting user data in the user plane.

An RRC state indicates whether an RRC layer of the UE is logicallyconnected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRCconnection is established between the RRC layer of the UE and the RRClayer of the E-UTRAN, the UE is in the RRC connected state(RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE).In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced.RRC_INACTIVE may be used for various purposes. For example, the massivemachine type communications (MMTC) UEs can be efficiently managed inRRC_INACTIVE. When a specific condition is satisfied, transition is madefrom one of the above three states to the other.

A predetermined operation may be performed according to the RRC state.In RRC_IDLE, public land mobile network (PLMN) selection, broadcast ofsystem information (SI), cell re-selection mobility, core network (CN)paging and discontinuous reception (DRX) configured by NAS may beperformed. The UE shall have been allocated an identifier (ID) whichuniquely identifies the UE in a tracking area. No RRC context stored inthe BS.

In RRC_CONNECTED, the UE has an RRC connection with the network (i.e.E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is alsoestablished for UE. The UE AS context is stored in the network and theUE. The RAN knows the cell which the UE belongs to. The network cantransmit and/or receive data to/from UE. Network controlled mobilityincluding measurement is also performed.

Most of operations performed in RRC_IDLE may be performed inRRC_INACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging isperformed in RRC_INACTIVE. In other words, in RRC_IDLE, paging formobile terminated (MT) data is initiated by core network and paging areais managed by core network. In RRC_INACTIVE, paging is initiated byNG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN.Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRXfor RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, inRRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established forUE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knowsthe RNA which the UE belongs to.

NAS layer is located at the top of the RRC layer. The NAS controlprotocol performs the functions, such as authentication, mobilitymanagement, security control.

The physical channels may be modulated according to OFDM processing andutilizes time and frequency as radio resources. The physical channelsconsist of a plurality of orthogonal frequency division multiplexing(OFDM) symbols in time domain and a plurality of subcarriers infrequency domain. One subframe consists of a plurality of OFDM symbolsin the time domain. A resource block is a resource allocation unit, andconsists of a plurality of OFDM symbols and a plurality of subcarriers.In addition, each subframe may use specific subcarriers of specific OFDMsymbols (e.g. first OFDM symbol) of the corresponding subframe for aphysical downlink control channel (PDCCH), i.e. L1/L2 control channel. Atransmission time interval (TTI) is a basic unit of time used by ascheduler for resource allocation. The TTI may be defined in units ofone or a plurality of slots, or may be defined in units of mini-slots.

The transport channels are classified according to how and with whatcharacteristics data are transferred over the radio interface. DLtransport channels include a broadcast channel (BCH) used fortransmitting system information, a downlink shared channel (DL-SCH) usedfor transmitting user traffic or control signals, and a paging channel(PCH) used for paging a UE. UL transport channels include an uplinkshared channel (UL-SCH) for transmitting user traffic or control signalsand a random access channel (RACH) normally used for initial access to acell.

Different kinds of data transfer services are offered by MAC sublayer.Each logical channel type is defined by what type of information istransferred. Logical channels are classified into two groups: controlchannels and traffic channels.

Control channels are used for the transfer of control plane informationonly. The control channels include a broadcast control channel (BCCH), apaging control channel (PCCH), a common control channel (CCCH) and adedicated control channel (DCCH). The BCCH is a DL channel forbroadcasting system control information. The PCCH is DL channel thattransfers paging information, system information change notifications.The CCCH is a channel for transmitting control information between UEsand network. This channel is used for UEs having no RRC connection withthe network. The DCCH is a point-to-point bi-directional channel thattransmits dedicated control information between a UE and the network.This channel is used by UEs having an RRC connection.

Traffic channels are used for the transfer of user plane informationonly. The traffic channels include a dedicated traffic channel (DTCH).The DTCH is a point-to-point channel, dedicated to one UE, for thetransfer of user information. The DTCH can exist in both UL and DL.

Regarding mapping between the logical channels and transport channels,in DL, BCCH can be mapped to BCH, BCCH can be mapped to DL-SCH, PCCH canbe mapped to PCH, CCCH can be mapped to DL-SCH, DCCH can be mapped toDL-SCH, and DTCH can be mapped to DL-SCH. In UL, CCCH can be mapped toUL-SCH, DCCH can be mapped to UL-SCH, and DTCH can be mapped to UL-SCH.

FIG. 7 illustrates a frame structure in a 3GPP based wirelesscommunication system.

The frame structure illustrated in FIG. 7 is purely exemplary and thenumber of subframes, the number of slots, and/or the number of symbolsin a frame may be variously changed. In the 3GPP based wirelesscommunication system, an OFDM numerology (e.g., subcarrier spacing(SCS), transmission time interval (TTI) duration) may be differentlyconfigured between a plurality of cells aggregated for one UE. Forexample, if a UE is configured with different SCSs for cells aggregatedfor the cell, an (absolute time) duration of a time resource (e.g. asubframe, a slot, or a TTI) including the same number of symbols may bedifferent among the aggregated cells. Herein, symbols may include OFDMsymbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbols).

Referring to FIG. 7, downlink and uplink transmissions are organizedinto frames. Each frame has Tf=10 ms duration. Each frame is dividedinto two half-frames, where each of the half-frames has 5 ms duration.Each half-frame consists of 5 subframes, where the duration Tsf persubframe is 1 ms. Each subframe is divided into slots and the number ofslots in a subframe depends on a subcarrier spacing. Each slot includes14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP,each slot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing Δf=2u*15 kHz. The following table shows thenumber of OFDM symbols per slot, the number of slots per frame, and thenumber of slots per for the normal CP, according to the subcarrierspacing Δf=2u*15 kHz.

TABLE 3 u Nslotsymb Nframe, uslot Nsubframe, uslot 0 14 10 1 1 14 20 2 214 40 4 3 14 80 8 4 14 160 16

The following table shows the number of OFDM symbols per slot, thenumber of slots per frame, and the number of slots per for the extendedCP, according to the subcarrier spacing Δf=2u*15 kHz.

TABLE 4 u Nslotsymb Nframe, uslot Nsubframe, uslot 2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the timedomain. For each numerology (e.g. subcarrier spacing) and carrier, aresource grid of Nsize,ugrid,x*NRBsc subcarriers and Nsubframe,usymbOFDM symbols is defined, starting at common resource block (CRB)Nstart,ugrid indicated by higher-layer signaling (e.g. radio resourcecontrol (RRC) signaling), where Nsize,ugrid,x is the number of resourceblocks (RBs) in the resource grid and the subscript x is DL for downlinkand UL for uplink. NRBsc is the number of subcarriers per RB. In the3GPP based wireless communication system, NRBsc is 12 generally. Thereis one resource grid for a given antenna port p, subcarrier spacingconfiguration u, and transmission direction (DL or UL). The carrierbandwidth Nsize,ugrid for subcarrier spacing configuration u is given bythe higher-layer parameter (e.g. RRC parameter). Each element in theresource grid for the antenna port p and the subcarrier spacingconfiguration u is referred to as a resource element (RE) and onecomplex symbol may be mapped to each RE. Each RE in the resource grid isuniquely identified by an index k in the frequency domain and an index 1representing a symbol location relative to a reference point in the timedomain. In the 3GPP based wireless communication system, an RB isdefined by 12 consecutive subcarriers in the frequency domain.

In the 3GPP NR system, RBs are classified into CRBs and physicalresource blocks (PRBs). CRBs are numbered from 0 and upwards in thefrequency domain for subcarrier spacing configuration u. The center ofsubcarrier 0 of CRB 0 for subcarrier spacing configuration u coincideswith ‘point A’ which serves as a common reference point for resourceblock grids. In the 3GPP NR system, PRBs are defined within a bandwidthpart (BWP) and numbered from 0 to NsizeBWP,i-1, where i is the number ofthe bandwidth part. The relation between the physical resource blocknPRB in the bandwidth part i and the common resource block nCRB is asfollows: nPRB=nCRB+NsizeBWP,i, where NsizeBWP,i is the common resourceblock where bandwidth part starts relative to CRB 0. The BWP includes aplurality of consecutive RBs. A carrier may include a maximum of N(e.g., 5) BWPs. A UE may be configured with one or more BWPs on a givencomponent carrier. Only one BWP among BWPs configured to the UE canactive at a time. The active BWP defines the UE's operating bandwidthwithin the cell's operating bandwidth.

In the present disclosure, the term “cell” may refer to a geographicarea to which one or more nodes provide a communication system, or referto radio resources. A “cell” of a geographic area may be understood ascoverage within which a node can provide service using a carrier and a“cell” as radio resources (e.g. time-frequency resources) is associatedwith bandwidth (BW) which is a frequency range configured by thecarrier. The “cell” associated with the radio resources is defined by acombination of downlink resources and uplink resources, for example, acombination of a downlink (DL) component carrier (CC) and a uplink (UL)CC. The cell may be configured by downlink resources only, or may beconfigured by downlink resources and uplink resources. Since DLcoverage, which is a range within which the node is capable oftransmitting a valid signal, and UL coverage, which is a range withinwhich the node is capable of receiving the valid signal from the UE,depends upon a carrier carrying the signal, the coverage of the node maybe associated with coverage of the “cell” of radio resources used by thenode. Accordingly, the term “cell” may be used to represent servicecoverage of the node sometimes, radio resources at other times, or arange that signals using the radio resources can reach with validstrength at other times.

In carrier aggregation (CA), two or more CCs are aggregated. A UE maysimultaneously receive or transmit on one or multiple CCs depending onits capabilities. CA is supported for both contiguous and non-contiguousCCs. When CA is configured the UE only has one radio resource control(RRC) connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell provides thenon-access stratum (NAS) mobility information, and at RRC connectionre-establishment/handover, one serving cell provides the security input.This cell is referred to as the Primary Cell (PCell). The PCell is acell, operating on the primary frequency, in which the UE eitherperforms the initial connection establishment procedure or initiates theconnection re-establishment procedure. Depending on UE capabilities,Secondary Cells (SCells) can be configured to form together with thePCell a set of serving cells. An SCell is a cell providing additionalradio resources on top of Special Cell. The configured set of servingcells for a UE therefore always consists of one PCell and one or moreSCells. For dual connectivity operation, the term Special Cell (SpCell)refers to the PCell of the master cell group (MCG) or the PSCell of thesecondary cell group (SCG). An SpCell supports PUCCH transmission andcontention-based random access, and is always activated. The MCG is agroup of serving cells associated with a master node, comprising of theSpCell (PCell) and optionally one or more SCells. The SCG is the subsetof serving cells associated with a secondary node, comprising of thePSCell and zero or more SCells, for a UE configured with dualconnectivity (DC). For a UE in RRC_CONNECTED not configured with CA/DCthere is only one serving cell comprising of the PCell. For a UE inRRC_CONNECTED configured with CA/DC the term “serving cells” is used todenote the set of cells comprising of the SpCell(s) and all SCells. InDC, two MAC entities are configured in a UE: one for the MCG and one forthe SCG.

FIG. 8 illustrates a data flow example in the 3GPP NR system.

In FIG. 8, “RB” denotes a radio bearer, and “H” denotes a header. Radiobearers are categorized into two groups: data radio bearers (DRB) foruser plane data and signalling radio bearers (SRB) for control planedata. The MAC PDU is transmitted/received using radio resources throughthe PHY layer to/from an external device. The MAC PDU arrives to the PHYlayer in the form of a transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH aremapped to their physical channels PUSCH and PRACH, respectively, and thedownlink transport channels DL-SCH, BCH and PCH are mapped to PDSCH,PBCH and PDSCH, respectively. In the PHY layer, uplink controlinformation (UCI) is mapped to PUCCH, and downlink control information(DCI) is mapped to PDCCH. A MAC PDU related to UL-SCH is transmitted bya UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCHis transmitted by a BS via a PDSCH based on a DL assignment.

Data unit(s) (e.g. PDCP SDU, PDCP PDU, RLC SDU, RLC PDU, RLC SDU, MACSDU, MAC CE, MAC PDU) in the present disclosure is(are)transmitted/received on a physical channel (e.g. PDSCH, PUSCH) based onresource allocation (e.g. UL grant, DL assignment). In the presentdisclosure, uplink resource allocation is also referred to as uplinkgrant, and downlink resource allocation is also referred to as downlinkassignment. The resource allocation includes time domain resourceallocation and frequency domain resource allocation. In the presentdisclosure, an uplink grant is either received by the UE dynamically onPDCCH, in a Random Access Response, or configured to the UEsemi-persistently by RRC. In the present disclosure, downlink assignmentis either received by the UE dynamically on the PDCCH, or configured tothe UE semi-persistently by RRC signalling from the BS.

FIG. 9 shows an example of a method for a measurement and reporting towhich technical features of the present disclosure can be applied.

Referring to FIG. 9, in step S901, a UE may receive a measurementconfiguration from a RAN node. The measurement configuration maycomprise a list of measurement objects (measObject), a list of reportconfigurations (reportConfig), and a list of measurement identifiers ID,measID). The measurement ID may be related to/correspond to acombination of a measurement object and a report configuration. Themeasurement object may indicate object information regarding an objectthe UE is supposed to measure. For example, the object information maycomprise a measurement frequency and/or a list of cells includingserving cell/neighbor cell(s). The report configuration may comprise acondition to perform an action corresponding to a report type in thereport configuration. For example, the condition may comprise a reportcondition that should be satisfied for the UE to transmit a measurementreport. For another example, the condition may comprise a mobilitycondition that should be satisfied for the UE to perform a conditionalmobility. If the report type is set to ‘condTriggerConfig’, thecondition may be the mobility condition. The report type may also bereferred to as a purpose of the condition.

In step S903, the UE may perform a measurement based on the measurementconfiguration. For example, the UE may measure the serving cell and/orthe neighbor cell(s) on the measurement frequency specified by themeasurement object, to obtain a measurement result for the serving celland/or the neighbor cell(s). The measurement result may comprise a cellquality/signal strength/signal quality/channel quality/channelstate/reference signal received power (RSRP)/reference signal receivedquality (RSRQ) of the serving cell and/or the neighbor cell(s).

In step S905, the UE may transmit a measurement report to the RAN node.The UE may transmit the measurement report comprising the measurementresult for the serving cell and/or the neighbor cell(s) to the RAN nodebased on the report configuration (e.g., when the report condition issatisfied).

According to various embodiments, the report condition may comprise atleast one of an event, time-to-trigger (TTT), offset value, or thresholdvalue9s). The report condition for an event may be satisfied if anentering condition for the event is satisfied for at least the TTT. Forexample, the entering condition for event A1 may be satisfied if a cellquality of a serving cell becomes better than a threshold. The enteringcondition for event A2 may be satisfied if a cell quality of a servingcell becomes worse than a threshold. The entering condition for event A3may be satisfied if a cell quality of a neighbor cell becomes betterthan that of a serving cell by an offset. The entering condition forevent A4 may be satisfied if a cell quality of a neighbor cell becomesbetter than a threshold. The entering condition for event A5 may besatisfied if a cell quality of a serving cell becomes worse than aserving cell threshold, and a cell quality of a neighbor cell becomesbetter than a neighbor cell threshold.

According to various embodiments, the measurement configuration maycomprise/be related to at least one of a measurement period, ameasurement gap, or a measurement gap repetition period. The measurementperiod refers to a time spacing between two consecutive moments at whicha measurement on a neighbor cell is performed and/or a cell quality ofthe neighbor cell is obtained. The measurement gap refers to a gap/timeperiod during which no transmission and reception happens for the UE tomeasure a neighbor cell/inter-frequency. The measurement gap repetitionperiod refers to a time interval in which successive measurement gapsrepetitively occurs. In other words, the measurement gap repetitionperiod refers to a time interval between successive measurement gaps.

FIG. 10 shows an example of a conditional mobility procedure to whichtechnical features of the present disclosure can be applied. The stepsillustrated in FIG. 10 can also be applied to a conditional handoverprocedure, conditional SN addition procedure and/or conditional SNchange procedure.

Referring to FIG. 10, in step S1001, the source cell may transmitmeasurement control message to the UE. The source cell may configure theUE measurement procedures according to the roaming and accessrestriction information and, for example, the available multiplefrequency band information through the measurement control message.Measurement control information provided by the source cell through themeasurement control message may assist the function controlling the UE'sconnection mobility. For example, the measurement control message maycomprise measurement configuration and/or report configuration.

In step S1003, the UE may transmit a measurement report message to thesource cell. The measurement report message may comprise a result ofmeasurement on neighbor cell(s) around the UE which can be detected bythe UE. The UE may generate the measurement report message according toa measurement configuration and/or measurement control information inthe measurement control message received in step S1001.

In step S1005, the source cell may make a mobility decision based on themeasurement report. For example, the source cell may make a mobilitydecision and determine candidate target cells (e.g., target cell 1 andtarget cell 2) for mobility among neighbor cells around the UE based ona result of measurement (e.g., signal quality, reference signal receivedpower (RSRP), reference signal received quality (RSRP)) on the neighborcells.

In step S1007, the source cell may transmit mobility request messages tothe target cell 1 and the target cell 2 which are determined in stepS1005. That is, the source cell may perform mobility preparation withthe target cell 1 and the target cell 2. The mobility request messagemay comprise necessary information to prepare the mobility at the targetside (e.g., target cell 1 and target cell 2).

In step S1009, each of the target cell 1 and the target cell 2 mayperform an admission control based on information included in themobility request message. The target cell may configure and reserve therequired resources (e.g., C-RNTI and/or RACH preamble). TheAS-configuration to be used in the target cell can either be specifiedindependently (i.e. an “establishment”) or as a delta compared to theAS-configuration used in the source cell (i.e. a “reconfiguration”).

In step S1011, the target cell and the target cell 2 may transmit amobility request acknowledge (ACK) message to the source cell. Themobility request ACK message may comprise information on resourcesreserved and prepared for a mobility. For example, the mobility requestACK message may comprise a transparent container to be sent to the UE asan RRC message to perform the mobility. The container may include a newC-RNTI, target gNB security algorithm identifiers for the selectedsecurity algorithms, a dedicated RACH preamble, and/or possibly someother parameters i.e. access parameters, SIBs. If RACH-less mobility isconfigured, the container may include timing adjustment indication andoptionally a preallocated uplink grant. The mobility request ACK messagemay also include RNL/TNL information for forwarding tunnels, ifnecessary. As soon as the source cell receives the mobility request ACKmessage, or as soon as the transmission of the conditional mobilitycommand is initiated in the downlink, data forwarding may be initiated.

In step S1013, the source cell may transmit a conditionalreconfiguration to the UE. The conditional reconfiguration may be alsoreferred to as (or, may comprise) conditional handover (CHO)configuration and/or a conditional mobility command (e.g., CHO command).The conditional configuration may comprise a conditional reconfigurationfor each of the candidate target cells (e.g., target cell 1, target cell2). For example, the conditional reconfiguration may comprise aconditional reconfiguration for the target cell 1, and a conditionalreconfiguration for the target cell 2. The conditional reconfigurationfor the target cell 1 may comprise a mobility condition for the targetcell 1, and a target cell configuration for the target cell 1. Thetarget cell configuration for the target cell 1 may comprise RRCreconfiguration parameters associated with a mobility to the target cell1, including information on resources reserved for the mobility to thetarget cell 1. Similarly, the conditional reconfiguration for the targetcell 2 may comprise a mobility condition for the target cell 2, and atarget cell configuration for the target cell 2. The target cellconfiguration for the target cell 2 may comprise RRC reconfigurationparameters associated with a mobility to the target cell 2, includinginformation on resources reserved for the mobility to the target cell 2.

The mobility condition may inform at least one measurement ID. Forexample, the mobility condition may inform at most 2 measurement IDs. Ifa mobility condition of a target cell informs a measurement ID which isrelated to a measurement object A and a report configuration B,evaluating the mobility condition may comprise determining whether ameasurement result on the measurement object A satisfies a reportcondition in the report configuration B. If the measurement result onthe measurement object A satisfies the report condition in the reportconfiguration B according to the evaluation of the mobility condition,the UE may determine that the mobility condition of the target cell issatisfied (or, the target cell/measurement result for the target cellsatisfies the mobility condition of the target cell), and perform amobility to the target cell.

In step S1015, the UE may perform an evaluation of the mobilitycondition for the candidate target cells (e.g., target cell 1, targetcell 2) and select a target cell for a mobility among the candidatetarget cells. For example, the UE may perform measurements on thecandidate target cells, and determine whether a candidate target cellsatisfies a mobility condition for the candidate target cell among thecandidate target cells based on a result of the measurements on thecandidate target cells. If the UE identifies that the target cell 1satisfies a mobility condition for the target cell 1, the UE may selectthe target cell 1 as a target cell for the mobility.

In step S1017, the UE may perform a random access to the selected targetcell (e.g., target cell 1). For example, the UE may transmit a randomaccess preamble to the target cell 1, and receive a random accessresponse comprising an uplink grant from the target cell 1. If RACH-lessmobility is configured, the step S1017 may be omitted, and the uplinkgrant may be provided in step S1013.

In step S1019, the UE may transmit a mobility complete message to thetarget cell 1. When the UE has successfully accessed the target cell 1(or, received uplink grant when RACH-less mobility is configured), theUE may transmit a mobility complete message comprising a C-RNTI toconfirm the mobility, along with uplink buffer status report, wheneverpossible, to the target cell 1 to indicate that the mobility procedureis completed for the UE. The target cell 1 may verify the C-RNTItransmitted in the mobility complete message.

In step S1021, the target cell 1 may transmit a sequence number (SN)status request message to the source cell. The target cell 1 may requestthe source cell to inform the target cell 1 of a SN of a packet thetarget cell 1 has to transmit after the mobility, via the SN statusrequest message.

In step S1023, the source cell may transmit a conditional mobilitycancellation message to the target cell 2 which is not selected as atarget cell for a mobility among the candidate target cells. Afterreceiving the conditional mobility cancellation message, the target cell2 may release resources that are reserved in case of a mobility.

In step S1025, the target cell 2 may transmit a conditional mobilitycancellation confirmation message to the source cell, as a response forthe conditional mobility cancellation message. The conditional mobilitycancellation confirmation message may inform that the target cell 2 hasreleased resources reserved in case of a mobility.

In step S1027, the source cell may transmit a SN status transfer messageto the target cell 1, as a response for the SN status request message.The SN status transfer message may inform the target cell 1 of a SN of apacket the target cell 1 has to transmit after the mobility.

In step S1029, the source cell may perform a data forwarding to thetarget cell 1. For example, the source cell may forward data receivedfrom a core network to the target cell 1 so that the target cell 1 cannow transmit the data to the UE.

According to various embodiments, the network may configure the UE withone or more candidate target SpCells in the conditional reconfiguration.The UE may evaluate the condition of each configured candidate targetSpCell. The UE may apply the conditional reconfiguration associated withone of the target SpCells which fulfils associated execution condition.The network may provide the configuration parameters for the targetSpCell in the ConditionalReconfiguration information element (IE).

The UE may perform the following actions based on a receivedConditionalReconfiguration IE:

1> if the ConditionalReconfiguration contains thecondReconfigToRemoveList:

2> perform conditional reconfiguration removal procedure;

1> if the ConditionalReconfiguration contains the condReconfigAddModList(i.e., a list of conditional reconfigurations/conditional mobilitycommands):

2> perform conditional reconfiguration addition/modification.

For conditional reconfiguration removal, the UE shall:

1> for each condReconfigId (i.e., ID of conditional reconfiguration)value included in the condReconfigToRemoveList that is part of thecurrent UE conditional reconfiguration in VarConditionalReconfig:

2> remove the entry with the matching condReconfigId from theVarConditionalReconfig.

The UE may not consider the message as erroneous if thecondReconfigToRemoveList includes any condReconfigId value that is notpart of the current UE configuration.

Conditional reconfiguration addition/modification is described as thefollowings. For each condReconfigId received in thecondReconfigToAddModList IE the UE shall:

1> if an entry with the matching condReconfigId exists in thecondReconfigToAddModList within the VarConditionalReconfig (i.e., a listof conditional reconfiguration(s) already stored in the UE):

2> if the entry in condReconfigToAddModList includes ancondExecutionCond (i.e., mobility condition);

3> replace the entry with the value received for this condReconfigId;

2> else:

3> keep the stored condExecutionCond as the target candidateconfiguration for this condReconfigId;

2> if the entry in condReconfigToAddModList includes an condRRCReconfig(i.e., target cell configuration):

2> replace the entry with the value received for this condReconfigId;

2> if the entry in condReconfigToAddModList does not include ancondRRCReconfig;

3> keep the stored condRRCReconfig as the target candidate configurationfor this condReconfigId;

1> else:

2> add a new entry for this condReconfigId within theVarConditionalReconfig;

1> perform conditional reconfiguration evaluation.

For conditional reconfiguration evaluation, the UE shall:

1> for each condReconfigId within the VarConditionalReconfig:

2> consider the cell which has a physical cell identity matching thevalue indicated in the ServingCellConfigCommon included in thereconfigurationWithSync in the received condRRCReconfig to be applicablecell;

2> for each measId included in the measIdList within VarMeasConfigindicated in the condExecutionCond associated to condReconfigId:

3> if the entry condition(s) applicable for this event associated withthe condReconfigId, i.e. the event corresponding with the condEventId(s)of the corresponding condTriggerConfig within VarConditionalReconfig, isfulfilled for the applicable cells for all measurements after layer 3filtering taken during the corresponding timeToTrigger defined for thisevent within the VarConditionalReconfig:

4> consider the event associated to that measId to be fulfilled;

3> if the leaving condition(s) applicable for this event associated withthe condReconfigId, i.e. the event corresponding with the condEventId(s)of the corresponding condTriggerConfig within VarConditionalReconfig, isfulfilled for the applicable cells for all measurements after layer 3filtering taken during the corresponding timeToTrigger defined for thisevent within the VarConditionalReconfig:

4> consider the event associated to that measId to be not fulfilled;

2> if event(s) associated to all measId(s) within condTriggerConfig fora target candidate cell within the stored condRRCReconfig are fulfilled:

3> consider the target candidate cell within the stored condRRCReconfig,associated to that condReconfigId, as a triggered cell;

3> initiate the conditional reconfiguration execution.

Up to 2 MeasIds can be configured for each condReconfigId. Theconditional handover event of the 2 MeasIds may have the same ordifferent event conditions, triggering quantity, time to trigger, andtriggering threshold.

For conditional reconfiguration execution, the UE shall:

1> if more than one triggered cell exists:

2> select one of the triggered cells as the selected cell forconditional reconfiguration execution;

1> for the selected cell of conditional reconfiguration execution:

2> apply the stored condRRCReconfig of the selected cell and perform amobility to the selected cell.

If multiple NR cells are triggered in conditional reconfigurationexecution, which one to select among the triggered cells for executionmay be based on UE implementations. For example, the UE may considerbeams and beam quality to select one of the triggered cells forexecution.

According to various embodiments, a list of conditional reconfigurationsmay be received via ConditionalReconfiguration message. The list ofconditional reconfiguration may contain the following information asshown in table 5:

TABLE 5 -- ASN1START -- TAG-CONDRECONFIGTOADDMODLIST-STARTCondReconfigToAddModList-r16 ::= SEQUENCE (SIZE (1..maxNrofCondCells-r16)) OF CondReconfigToAddMod-r16CondReconfigToAddMod-r16 ::= SEQUENCE { condReconfigId-r16CondReconfigId-r16, condExecutionCond-r16 SEQUENCE (SIZE (1..2)) OFMeasId OPTIONAL, -- Cond condReconfigAdd condRRCReconfig-r16 OCTETSTRING (CONTAINING RRCReconfiguration) OPTIONAL, -- Cond condReconfigAdd... } -- TAG-CONDRECONFIGTOADDMODLIST-STOP -- ASN1STOP

According to table 5, CondReconfigToAddModList (i.e., list ofconditional reconfigurations) may be a list of CondReconfigToAddMod(i.e., conditional reconfiguration). Each CondReconfigToAddMod maycomprise CondReconfigId (i.e., ID of conditional reconfiguration),condExecutionCond (i.e., mobility condition), and condRRCReconfig (i.e.,target cell configuration). The condExecutionCond may be an executioncondition that needs to be fulfilled in order to trigger the executionof the conditional reconfiguration. At most 2 measurement IDs may berelated to/correspond to the condExecutionCond. The condRRCReconfig maybe an RRCReconfiguation message to be applied when the condition(s) arefullfied.

In the present disclosure, various timers can be defined for a mobilityand/or a conditional mobility. For example, T304 timer and T310 timermay be defined. When the UE starts and/or stops the timer and what theUE performs at the expiry of the timer are described in table 6 below:

TABLE 6 Timer Start Stop At expiry T304 Upon reception of Uponsuccessful For T304 of MCG, in case of RRCReconfiguraition completion ofthe handover from NR or message including random access on the intra-NRhandover, initiate reconfigurationWithSync corresponding the RRCre-establishment or upon conditional SpCell procedure; In case ofreconfiguration For T304 of SCG, handover to NR, perform the executioni.e. when upon SCG release actions defined in the applying a storedspecifications applicable for RRCReconfiguration the source RAT. If anyDAPS message including bearer is configured and ifreconfigurationWithSync. there is no RLF in source PCell, initiate thefailure information procedure. For T304 of SCG, inform network about thereconfiguration with sync failure by initiating the SCG failureinformation procedure. T310 Upon detecting Upon receiving N311 If theT310 is kept in MCG: If physical layer consecutive in-sync AS securityis not activated: problems for the indications from go to RRC_IDLE else:SpCell i.e. upon lower layers for the initiate the MCG failure receivingN310 SpCell, upon information procedure or the consecutive receivingconnection re-establishment out-of-sync RRCReconfiguration procedure ordeclare a radio indications from with link failure (RLF) if any lowerlayers. reconfigurationWith DAPS bearer is configured. Sync for thatcell If the T310 is kept in SCG, group, upon Inform E-UTRAN/NR aboutreception of the SCG radio link failure by MobilityFromNRCommand,initiating the SCG failure upon the information procedure.reconfiguration of rlf-TimersAndConstant, upon initiating the connectionre-establishment procedure, and upon initiating the MCG failureinformation procedure. Upon SCG release, if the T310 is kept in SCG.

According to various embodiments, the UE shall not stop T310 timer andshall not start T304 timer when the UE receives a configuration of CHOcandidate (i.e., when the UE receives one or more conditional mobilitycommands). The T310 timer may be stopped and the T304-like timer (or,T304 timer) may be started when the UE begins execution of a conditionalmobility for a target cell. That is, the T304-like timer (or, T304timer) may be started upon/after initiating the conditional mobility tothe target cell, and/or started upon/after determining that a mobilitycondition for the target cell is satisfied.

According to various embodiments, at RLF, the UE may perform a cellselection, and if the selected cell is a conditional mobility candidate(i.e., a cell which is configured for conditional mobility), then the UEmay attempt to perform a conditional mobility execution; otherwise, RRCconnection re-establishment may be performed.

At legacy mobility failure (i.e., T304 timer expiry) or failure toaccess a first conditional mobility candidate cell (i.e., T304-liketimer expiry), the UE may perform a cell selection and if the selectedcell is a second conditional mobility candidate cell, then the UE mayattempt to perform a conditional mobility execution; otherwise, RRCconnection re-establishment may be performed. The first conditionalmobility candidate cell and the second conditional mobility candidatecell may be the same, or different from each other.

FIGS. 11A, 11B and 11C show an example of a measurement ID swapping towhich technical features of the present disclosure can be applied.

Measurement ID swapping may be performed upon inter-frequencymobility/handover and/or RRC re-establishment.

In FIG. 11A, the state before inter-frequencymobility/handover/re-establishment is shown. The UE may performinter-frequency measurements on measObject 2 and 3. Since measurementgaps are being used to measure measObject 2 and 3, event Al may also beconfigured on the serving frequency (measObject 1) so that when theserving cell quality improves, measurement gaps can be stopped.

If inter-frequency mobility/handover/re-establishment is performedtowards measObject 2, measurement ID swapping may be performed as shownin FIG. 11B, since the measObject corresponding to the mobility/handovertarget already existed (measObject 2 in this case). However, as shown inFIG. 11C, if inter-frequency mobility/handover/re-establishment isperformed towards an inter-frequency for which no measObject has beenconfigured (measObject X in FIG. 11C), measId's previously linked to theserving frequency (measObject 1) may be implicitly removed.

Any measurement configuration received within the mobility/handovercommand or the first reconfiguration after re-establishment may beprocessed after performing the implicit swapping/removal of themeasID(s).

A conditional handover (CHO) is being introduced to avoid a handoverfailure that may happen due to, for example, a reception of handoverfailure. In a conditional handover, a UE may receive a CHO command priorto actual handover timing so as to increase the probability of successhandover. The CHO command may include CHO execution condition(s) andtarget cell configuration(s) each of which corresponds to differenttarget cell(s) respectively. After receiving the CHO command, the UE mayevaluate CHO execution condition. If at least one target cell satisfiesthe CHO execution condition, the UE may initiate access to thecorresponding target cell using the target cell configuration for thecorresponding target cell. For a conditional handover, more than onetarget cell can be prepared for the handover. In case of preparation ofmultiple target cells for CHO, a UE may receive a CHO command includingmultiple target cell configurations corresponding to the prepared targetcells.

It has been discussed whether the UE keeps the CHO command after HOcomplete to one of the candidate cells and how to design the CHOconfiguration (i.e., how to specify CHO configuration). For example,measurement identity (MeasId) may be reused as an execution condition toperform CHO, and the purpose of measId may be added to the reportconfiguration which is linked to the measId. That is, UE may perform CHOwhen report condition which is linked to a measId is met. The purpose ofthe report condition may also be set to CHO execution.

However, the UE may perform additional actions related to measurementhandling after handover completion in which measurement objects whichare linked to the measId are swapped and/or are released to preventinappropriate measurement procedure. Thus, if the measId is reused as aCHO execution condition, the UE may not be likely to release themeasurement configuration for the CHO even though the UE should releasethe CHO configuration after handover complete. Then the measId(s) mayremain in the measurement configuration so that unnecessary events ofconditions can be met without target cell configuration.

Furthermore, there would be an additional configuration failure scenarioif the the CHO configuration is kept after handover complete. When theUE swapped the measId, the swapped measID may correspond to CHOexecution condition for CHO from the target frequency to the sourcefrequency after CHO complete. That is, the executed CHO condition maybecome a new CHO execution condition for the source frequency which maycause fall-back handover to the source cell in the near future. Then ifa new CHO execution condition for the source frequency is met beforereceiving an updated CHO command from the network, there may be anambiguity scenario that a CHO execution condition that doesn't have avalid target cell configuration for mobility is met. This error casescenario may be worse if the UE is able to support the enhanced CHOfailure handling. For example, the UE can retry the CHO procedure toother candidate cell after failure of the CHO trial, if there aremultiple candidate cells for the CHO command and a newly selected cellis in the list of the candidate cells after the CHO failure. Wheneverthe UE fails to perform the CHO to a candidate cell, the UE may excludethe target cell configuration for the corresponding candidate cell, butthe UE may keep the corresponding measurement configuration. Therefore,a way of avoiding ambiguous scenario which may cause invalidconfiguration handling should be needed.

According to various embodiments of the present disclosure, upon/aftersuccessful mobility (e.g., CHO) complete, the UE may be able to handlethe invalid scenario that the UE doesn't have a target cellconfiguration for performing a mobility to the target cell when thecorresponding mobility execution condition is met. For example, in ascenario that the UE doesn't have a target cell configuration forperforming a mobility to the target cell when the corresponding mobilityexecution condition is met, the UE may:

1) apply a previous version of the target cell configuration for themobility when the target cell configuration is not available but the UEhas any previous version of the target cell configuration; and/or

2) report measurement results and/or transmit a measurement report toindicate that the UE is ready to perform a mobility to a cell but thereis no available target cell configuration for the cell.

FIG. 12 shows an example of a method for handling a conditional mobilitycommand after performing a conditional mobility according to anembodiment of the present disclosure. Steps illustrated in FIG. 12 maybe performed by a wireless device and/or a UE.

Referring to FIG. 12, in step S1201, the wireless device may identify afirst cell which satisfies a mobility condition for the first cellincluded in the conditional mobility command of the first cell. Thewireless device may identify that the first cell and/or a measurementresult on the first cell satisfied the mobility condition for the firstcell.

In step S1203, the wireless device may determine that a target cellconfiguration for the first cell is unavailable. When the wirelessdevice can determine that the target cell configuration for the firstcell is unavailable will be described later.

In step S1205, after/based on a determination that the target cellconfiguration for the first cell is unavailable, the wireless device maytransmit a report comprising information for an unavailability of thetarget cell configuration for the first cell. The information mayindicate that the target cell configuration for the first cell isunavailable. For example, the report may be transmitted via ameasurement report, which may include measurement result(s) on one ormore cells.

According to various embodiments, the wireless device may receiveconditional mobility commands of target cells. Each of the conditionalmobility commands may be related to each of the target cells, and theconditional mobility commands may comprise a conditional mobilitycommand of a second cell among the target cells. The wireless device mayperform a mobility to the second cell by applying a target cellconfiguration for the second cell in the conditional mobility command ofthe second cell, before identifying the first cell and transmitting thereport. The steps S1201 to S1205 may be performed while the wirelessdevice is being served by the second cell as a serving cell.

According to various embodiments, after performing the mobility to thesecond cell, the wireless device may transmit the report based on adetermination that the first cell satisfies the mobility condition forthe first cell, and the target cell configuration for the first cell isunavailable.

According to various embodiments, based on identifying that a mobilitycondition for the second cell is satisfied, the wireless device mayperform the mobility to the second cell. For example, the wirelessdevice may evaluate the mobility condition for the second cell based ona measurement result on the second cell and/or may determine whether themobility condition for the second cell is satisfied based on ameasurement result on the second cell. The wireless device may identifythat the mobility condition for the second cell is satisfied accordingto the evaluation. The mobility condition for the second cell may beincluded in the conditional mobility command of the second cell.

According to various embodiments, the mobility condition for the secondcell may become the mobility condition for the second cell according toa measurement identity swapping after performing the mobility from thefirst cell to the second cell. The target cell configuration for thefirst cell may be determined as being unavailable based on that themobility is performed from the first cell to the second cell.

According to various embodiments, the conditional mobility commands maycomprise the conditional mobility command of the first cell among thetarget cells. The wireless device may initiate the mobility to the firstcell, and start a timer (e.g., T304 timer or T304-like timer) basedon/upon/after identifying that the mobility condition for the first cellis satisfied. After/upon an expiry of the timer (that is, if themobility to the first cell is not succeed while the timer is running andthe timer expires), the wireless device may remove the target cellconfiguration for the first cell and performing a cell selection. Thewireless device may perform the mobility to the second cell based onidentifying that a cell to which the cell selection is performed isidentical to the second cell.

According to various embodiments, the target cell configuration for thefirst cell may be determined as being unavailable based on that thetarget cell configuration for the first cell has been removed.

According to various embodiments, the wireless device may performmobility to the first cell by applying a stored target cellconfiguration for the first cell based on a determination that thetarget cell configuration for the first cell is unavailable. The storedtarget cell configuration for the first cell may not be obtained by theconditional mobility command of the first cell.

According to various embodiments, the wireless device may receive amobility command which has one or more target cell configurations andone or more conditions for a mobility. The wireless device may checkwhether a target cell configuration is available for a cell among theone or more target cells upon a condition for the mobility being met forthe cell. In this case, the wireless device may i) apply a previousversion of the target cell configuration for the mobility based on thatthe target cell configuration being not available but the UE having theprevious version of the target cell configuration; and/or reportmeasurement results to inform that there is no available target cellconfiguration for the cell;

FIG. 13 shows an example of a method for a CHO command handling aftercompleting a CHO according to an embodiment of the present disclosure.In FIG. 13, descriptions regarding a handover/CHO are exemplary, and thedescriptions may also be applied to a mobility/conditional mobility(e.g., SN addition and/or SN change). Steps illustrated in FIG. 13 maybe performed by a wireless device and/or a UE.

Referring to FIG. 13, in step S1301, the UE may attempt to perform aconditional mobility to a target cell by applying a target cellconfiguration for the target cell in a conditional mobility command. TheUE may receive a CHO command that is a mobility command including one ormore CHO execution conditions and one or more target cell configurationsincluding HO validity timer (i.e., T304 or T304-like timer). For the CHOexecution condition, an identity (e.g., measurement ID) may beconfigured and the identity may be linked to/related to a measurementconfiguration (e.g., measurement object and/or report configuration)which has been already configured or to be configured via the CHOcommand for the CHO execution condition. The UE may be able to perform aCHO mobility to a target cell based on a CHO command of the target cell,if a condition specified by a measurement configuration related to acorresponding measurement identity is met while performing themeasurement. When performing the CHO mobility, the UE may start the HOvalidity timer (e.g., T304 timer or T304-like timer). For example, theUE may start the HO validity timer upon/after receiving the CHO command.For another example, the UE may start the HO validity timer upon/afterinitiating the CHO mobility. For another example, the UE may start theHO validity timer upon/after determining that a mobility condition forthe target cell is satisfied.

In step S1303, the UE may determine whether the CHO mobility to thetarget cell is succeeded. For example, if the UE cannot succeed the CHOmobility to the target cell until the expiry of the HO validity timerand the HO validity timer expires, the UE may perform step

S1305. For another example, if the UE succeeds in CHO mobility to thetarget cell before the expiry of the HO validity timer and the UE stopsthe HO validity timer (i.e., HO validity timer does not expire), the UEmay perform step 1311.

In step S1305, the UE may exclude the target cell configuration for thetarget cell from the CHO command. The UE may remove/invalidate thetarget cell configuration for the target cell. As a consequence of stepS1307, the target cell configuration for the target cell may becomeunavailable.

In step S1307, the UE may perform a cell selection. The UE may notremove the corresponding (measurement) identity (e.g., measID), becausethe identity was just reused from the current measurement configurationbut the UE may not perform measurement for the identity for which theCHO is failed.

In step S1309, if a newly selected cell is one of target cells in theCHO command, the UE may perform the CHO mobility again to the newlyselected cell, and the UE may start the HO validity timer again. Then,the UE may go back to step S1303.

In step S1311, the UE may perform a measurement configuration/IDswapping procedure. The UE may swap measurement configurations that arerelated to the source cell and the target cell, as illustrated in FIGS.11A, B and C. For example, if the measurement configurations are relatedto the target cell before performing the CHO, the measurementconfigurations may be changed for a source frequency. That is, among allmeasId list, if any measId links the measurement object of the sourcecell before the CHO to a measurement configuration, the measId maychange the linking to the measurement object of the target cell beforethe CHO. If the measurement configurations are related to the sourcecell before performing the CHO, the measurement configurations may bechanged for a target frequency (i.e., new source cell after CHO). Incase there are no measurement configurations of the target cell, the UEmay remove the measurement configurations which are related to thesource cell.

In step S1313, after the procedure of measurement configurationswapping, the UE may keep performing a measurement to check whether anyCHO execution condition is met according to the CHO command. When acertain CHO execution condition for a new target cell is met for theexisting CHO command before the network provides an updated CHO command,the UE may check that there is stored target cell configuration in theCHO command. If the new target cell is the source cell before the CHO orthe target cell for which the CHO mobility was failed and which wasexcluded by the expiry of the HO validity timer in the previous CHOprocedure, the UE cannot perform the CHO mobility because there is notarget cell configuration to comply/apply.

In step S1315, the UE may check that any stored target cellconfiguration which may not be received by the CHO command exists, andthe UE may apply a previous version of the target cell configuration forthe CHO mobility procedure. As another option, the UE may reportmeasurement results and/or perform measurement reporting, to indicatethat the UE is ready to perform a mobility to a cell but there is noavailable target cell configuration for the cell.

As described above, the UE may consider one or more target cells whichsatisfied a mobility condition as triggered cells, and may select one ofthe triggered cells as the selected cell for conditional reconfigurationexecution. Upon selecting one target candidate cell for conditionalreconfiguration, the UE shall:

1> if the UE is able to comply with the stored RRCReconfiguration (i.e.,target cell configuration) of conditional reconfiguration for theselected cell:

2> apply the stored RRCReconfiguration and perform a mobility to theselected cell;

1> else:

2> if the UE is able to comply with any available version ofRRCReconfiguration for the selected cell:

3> apply the available version of RRCReconfiguration and perform amobility to the selected cell;

2> if the UE is capable to report the measurement result to indicatethat the UE is not able to comply with the stored RRCReconfiguration ofconditional reconfiguration for the selected cell:

3> initiate the measurement reporting procedure;

2> else:

3> perform the reconfiguration failure procedure.

For measurement reporting, the UE shall:

1> if the reportType is set to condTriggerConfig (i.e., if a conditioninformed by measId is set to a mobility condition); and if the UE is notable to comply with and/or apply the stored RRCReconfiguration ofconditional reconfiguration for the selected cell:

2> set the measId to the measurement identity that triggered theconditional reconfiguration;

2> include the selected cell for the conditional reconfiguration;

2> set the failureCause to the value noCellConfiguration;

FIG. 14 shows a UE to implement an embodiment of the present disclosure.The present disclosure described above for UE side may be applied tothis embodiment. The UE in FIG. 14 may be an example of first device 214as illustrated in FIG. 2.

A UE includes a processor 1410 (i.e., processor 211), a power managementmodule 1411, a battery 1412, a display 1413, a keypad 1414, a subscriberidentification module (SIM) card 1415, a memory 1420 (i.e., memory 212),a transceiver 1430 (i.e., transceiver 213), one or more antennas 1431, aspeaker 1440, and a microphone 1441.

A UE includes a processor 1410, a power management module 1411, abattery 1412, a display 1413, a keypad 1414, a subscriber identificationmodule (SIM) card 1415, a memory 1420, a transceiver 1430, one or moreantennas 1431, a speaker 1440, and a microphone 1441.

The processor 1410 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 1410. Theprocessor 1410 may include application-specific integrated circuit(ASIC), other chipset, logic circuit and/or data processing device. Theprocessor 1410 may be an application processor (AP). The processor 1410may include at least one of a digital signal processor (DSP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a modem(modulator and demodulator). An example of the processor 1410 may befound in SNAPDRAGON™ series of processors made by Qualcomm®, EXYNOS™series of processors made by Samsung®, A series of processors made byApple®, HELIO™ series of processors made by MediaTek®, ATOM™ series ofprocessors made by Intel® or a corresponding next generation processor.

The processor 1410 may be configured to, or configured to control thetransceiver 1430 to implement steps performed by the UE and/or thewireless device throughout the disclosure.

The power management module 1411 manages power for the processor 1410and/or the transceiver 1430. The battery 1412 supplies power to thepower management module 1411. The display 1413 outputs results processedby the processor 1410. The keypad 1414 receives inputs to be used by theprocessor 1410. The keypad 1414 may be shown on the display 1413. TheSIM card 1415 is an integrated circuit that is intended to securelystore the international mobile subscriber identity (IMSI) number and itsrelated key, which are used to identify and authenticate subscribers onmobile telephony devices (such as mobile phones and computers). It isalso possible to store contact information on many SIM cards.

The memory 1420 is operatively coupled with the processor 1410 andstores a variety of information to operate the processor 1410. Thememory 1420 may include read-only memory (ROM), random access memory(RAM), flash memory, memory card, storage medium and/or other storagedevice. When the embodiments are implemented in software, the techniquesdescribed herein can be implemented with modules (e.g., procedures,functions, and so on) that perform the functions described herein. Themodules can be stored in the memory 1420 and executed by the processor1410. The memory 1420 can be implemented within the processor 1410 orexternal to the processor 1410 in which case those can becommunicatively coupled to the processor 1410 via various means as isknown in the art.

The transceiver 1430 is operatively coupled with the processor 1410, andtransmits and/or receives a radio signal. The transceiver 1430 includesa transmitter and a receiver. The transceiver 1430 may include basebandcircuitry to process radio frequency signals. The transceiver 1430controls the one or more antennas 1431 to transmit and/or receive aradio signal.

The speaker 1440 outputs sound-related results processed by theprocessor 1410. The microphone 1441 receives sound-related inputs to beused by the processor 1410.

According to various embodiments, the processor 1410 may be configuredto, or configured to control the transceiver 1430 to implement stepsperformed by the UE and/or the wireless device throughout thedisclosure. For example, the processor 1410 may configured to identify afirst cell which satisfies a mobility condition for the first cellincluded in a conditional mobility command of the first cell. Theprocessor 1410 may configured to control the transceiver 1430 totransmit, based on a determination that a target cell configuration forthe first cell is unavailable, a report comprising information for anunavailability of the target cell configuration for the first cell.

FIG. 15 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

Referring to FIG. 15, the wireless communication system may include afirst device 1510 (i.e., first device 210) and a second device 1520(i.e., second device 220).

The first device 1510 may include at least one transceiver, such as atransceiver 1511, and at least one processing chip, such as a processingchip 1512. The processing chip 1512 may include at least one processor,such a processor 1513, and at least one memory, such as a memory 1514.The memory may be operably connectable to the processor 1513. The memory1514 may store various types of information and/or instructions. Thememory 1514 may store a software code 1515 which implements instructionsthat, when executed by the processor 1513, perform operations of thefirst device 910 described throughout the disclosure. For example, thesoftware code 1515 may implement instructions that, when executed by theprocessor 1513, perform the functions, procedures, and/or methods of thefirst device 1510 described throughout the disclosure. For example, thesoftware code 1515 may control the processor 1513 to perform one or moreprotocols. For example, the software code 1515 may control the processor1513 to perform one or more layers of the radio interface protocol.

The second device 1520 may include at least one transceiver, such as atransceiver 1521, and at least one processing chip, such as a processingchip 1522. The processing chip 1522 may include at least one processor,such a processor 1523, and at least one memory, such as a memory 1524.The memory may be operably connectable to the processor 1523. The memory1524 may store various types of information and/or instructions. Thememory 1524 may store a software code 1525 which implements instructionsthat, when executed by the processor 1523, perform operations of thesecond device 1520 described throughout the disclosure. For example, thesoftware code 1525 may implement instructions that, when executed by theprocessor 1523, perform the functions, procedures, and/or methods of thesecond device 1520 described throughout the disclosure. For example, thesoftware code 1525 may control the processor 1523 to perform one or moreprotocols. For example, the software code 1525 may control the processor1523 to perform one or more layers of the radio interface protocol.

According to various embodiments, the first device 1510 as illustratedin FIG. 15 may comprise a wireless device. The wireless device maycomprise a transceiver 1511, a processing chip 1512. The processing chip1512 may comprise a processor 1513, and a memory 1514. The memory 1514may be operably connectable to the processor 1513. The memory 1514 maystore various types of information and/or instructions. The memory 1514may store a software code 1515 which implements instructions that, whenexecuted by the processor 1513, perform operations comprising:identifying a first cell which satisfies a mobility condition for thefirst cell included in a conditional mobility command of the first cell;and based on a determination that a target cell configuration for thefirst cell is unavailable, transmitting a report comprising informationfor an unavailability of the target cell configuration for the firstcell.

The present disclosure may be applied to various future technologies,such as AI, robots, autonomous-driving/self-driving vehicles, and/orextended reality (XR).

<AI>

AI refers to artificial intelligence and/or the field of studyingmethodology for making it. Machine learning is a field of studyingmethodologies that define and solve various problems dealt with in AI.Machine learning may be defined as an algorithm that enhances theperformance of a task through a steady experience with any task.

An artificial neural network (ANN) is a model used in machine learning.It can mean a whole model of problem-solving ability, consisting ofartificial neurons (nodes) that form a network of synapses. An ANN canbe defined by a connection pattern between neurons in different layers,a learning process for updating model parameters, and/or an activationfunction for generating an output value. An ANN may include an inputlayer, an output layer, and optionally one or more hidden layers. Eachlayer may contain one or more neurons, and an ANN may include a synapsethat links neurons to neurons. In an ANN, each neuron can output asummation of the activation function for input signals, weights, anddeflections input through the synapse. Model parameters are parametersdetermined through learning, including deflection of neurons and/orweights of synaptic connections. The hyper-parameter means a parameterto be set in the machine learning algorithm before learning, andincludes a learning rate, a repetition number, a mini batch size, aninitialization function, etc. The objective of the ANN learning can beseen as determining the model parameters that minimize the lossfunction. The loss function can be used as an index to determine optimalmodel parameters in learning process of ANN.

Machine learning can be divided into supervised learning, unsupervisedlearning, and reinforcement learning, depending on the learning method.Supervised learning is a method of learning ANN with labels given tolearning data. Labels are the answers (or result values) that ANN mustinfer when learning data is input to ANN. Unsupervised learning can meana method of learning ANN without labels given to learning data.Reinforcement learning can mean a learning method in which an agentdefined in an environment learns to select a behavior and/or sequence ofactions that maximizes cumulative compensation in each state.

Machine learning, which is implemented as a deep neural network (DNN)that includes multiple hidden layers among ANN, is also called deeplearning. Deep learning is part of machine learning. In the following,machine learning is used to mean deep learning.

FIG. 16 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

The AI device 1600 may be implemented as a stationary device or a mobiledevice, such as a TV, a projector, a mobile phone, a smartphone, adesktop computer, a notebook, a digital broadcasting terminal, a PDA, aPMP, a navigation device, a tablet PC, a wearable device, a set-top box(STB), a digital multimedia broadcasting (DMB) receiver, a radio, awashing machine, a refrigerator, a digital signage, a robot, a vehicle,etc.

Referring to FIG. 16, the AI device 1600 may include a communicationpart 1610, an input part 1620, a learning processor 1630, a sensing part1640, an output part 1650, a memory 1660, and a processor 1670.

The communication part 1610 can transmit and/or receive data to and/orfrom external devices such as the AI devices and the AI server usingwire and/or wireless communication technology. For example, thecommunication part 1610 can transmit and/or receive sensor information,a user input, a learning model, and a control signal with externaldevices. The communication technology used by the communication part1610 may include a global system for mobile communication (GSM), a codedivision multiple access (CDMA), an LTE/LTE-A, a 5G, a WLAN, a Wi-Fi,Bluetooth™, radio frequency identification (RFID), infrared dataassociation (IrDA), ZigBee, and/or near field communication (NFC).

The input part 1620 can acquire various kinds of data. The input part1620 may include a camera for inputting a video signal, a microphone forreceiving an audio signal, and a user input part for receivinginformation from a user. A camera and/or a microphone may be treated asa sensor, and a signal obtained from a camera and/or a microphone may bereferred to as sensing data and/or sensor information. The input part1620 can acquire input data to be used when acquiring an output usinglearning data and a learning model for model learning. The input part1620 may obtain raw input data, in which case the processor 1670 or thelearning processor 1630 may extract input features by preprocessing theinput data.

The learning processor 1630 may learn a model composed of an ANN usinglearning data. The learned ANN can be referred to as a learning model.The learning model can be used to infer result values for new input datarather than learning data, and the inferred values can be used as abasis for determining which actions to perform. The learning processor1630 may perform AI processing together with the learning processor ofthe AI server. The learning processor 1630 may include a memoryintegrated and/or implemented in the AI device 1600. Alternatively, thelearning processor 1630 may be implemented using the memory 1660, anexternal memory directly coupled to the AI device 1600, and/or a memorymaintained in an external device.

The sensing part 1640 may acquire at least one of internal informationof the AI device 1600, environment information of the AI device 1600,and/or the user information using various sensors. The sensors includedin the sensing part 1640 may include a proximity sensor, an illuminancesensor, an acceleration sensor, a magnetic sensor, a gyro sensor, aninertial sensor, an RGB sensor, an IR sensor, a fingerprint recognitionsensor, an ultrasonic sensor, an optical sensor, a microphone, a lightdetection and ranging (LIDAR), and/or a radar.

The output part 1650 may generate an output related to visual, auditory,tactile, etc. The output part 1650 may include a display unit foroutputting visual information, a speaker for outputting auditoryinformation, and/or a haptic module for outputting tactile information.

The memory 1660 may store data that supports various functions of the AIdevice 1600. For example, the memory 1660 may store input data acquiredby the input part 1620, learning data, a learning model, a learninghistory, etc.

The processor 1670 may determine at least one executable operation ofthe AI device 1600 based on information determined and/or generatedusing a data analysis algorithm and/or a machine learning algorithm. Theprocessor 1670 may then control the components of the AI device 1600 toperform the determined operation. The processor 1670 may request,retrieve, receive, and/or utilize data in the learning processor 1630and/or the memory 1660, and may control the components of the AI device1600 to execute the predicted operation and/or the operation determinedto be desirable among the at least one executable operation. Theprocessor 1670 may generate a control signal for controlling theexternal device, and may transmit the generated control signal to theexternal device, when the external device needs to be linked to performthe determined operation. The processor 1670 may obtain the intentioninformation for the user input and determine the user's requirementsbased on the obtained intention information. The processor 1670 may useat least one of a speech-to-text (STT) engine for converting speechinput into a text string and/or a natural language processing (NLP)engine for acquiring intention information of a natural language, toobtain the intention information corresponding to the user input. Atleast one of the STT engine and/or the NLP engine may be configured asan ANN, at least a part of which is learned according to a machinelearning algorithm. At least one of the STT engine and/or the NLP enginemay be learned by the learning processor 1630 and/or learned by thelearning processor of the AI server, and/or learned by their distributedprocessing. The processor 1670 may collect history information includingthe operation contents of the AI device 1600 and/or the user's feedbackon the operation, etc. The processor 1670 may store the collectedhistory information in the memory 1660 and/or the learning processor1630, and/or transmit to an external device such as the AI server. Thecollected history information can be used to update the learning model.The processor 1670 may control at least some of the components of AIdevice 1600 to drive an application program stored in memory 1660.Furthermore, the processor 1670 may operate two or more of thecomponents included in the AI device 1600 in combination with each otherfor driving the application program.

FIG. 17 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

Referring to FIG. 17, in the AI system, at least one of an AI server1720, a robot 1710 a, an autonomous vehicle 1710 b, an XR device 1710 c,a smartphone 1710 d and/or a home appliance 1710 e is connected to acloud network 1700. The robot 1710 a, the autonomous vehicle 1710 b, theXR device 1710 c, the smartphone 1710 d, and/or the home appliance 1710e to which the AI technology is applied may be referred to as AI devices1710 a to 1710 e.

The cloud network 1700 may refer to a network that forms part of a cloudcomputing infrastructure and/or resides in a cloud computinginfrastructure. The cloud network 1700 may be configured using a 3Gnetwork, a 4G or LTE network, and/or a 5G network. That is, each of thedevices 1710 a to 1710 e and 1720 consisting the AI system may beconnected to each other through the cloud network 1700. In particular,each of the devices 1710 a to 1710 e and 1720 may communicate with eachother through a base station, but may directly communicate with eachother without using a base station.

The AI server 1720 may include a server for performing AI processing anda server for performing operations on big data. The AI server 1720 isconnected to at least one or more of AI devices constituting the AIsystem, i.e. the robot 1710 a, the autonomous vehicle 1710 b, the XRdevice 1710 c, the smartphone 1710 d and/or the home appliance 1710 ethrough the cloud network 1700, and may assist at least some AIprocessing of the connected AI devices 1710 a to 1710 e. The AI server1720 can learn the ANN according to the machine learning algorithm onbehalf of the AI devices 1710 a to 1710 e, and can directly store thelearning models and/or transmit them to the AI devices 1710 a to 1710 e.The AI server 1720 may receive the input data from the AI devices 1710 ato 1710 e, infer the result value with respect to the received inputdata using the learning model, generate a response and/or a controlcommand based on the inferred result value, and transmit the generateddata to the AI devices 1710 a to 1710 e. Alternatively, the AI devices1710 a to 1710 e may directly infer a result value for the input datausing a learning model, and generate a response and/or a control commandbased on the inferred result value.

Various embodiments of the AI devices 1710 a to 1710 e to which thetechnical features of the present disclosure can be applied will bedescribed. The AI devices 1710 a to 1710 e shown in FIG. 17 can be seenas specific embodiments of the AI device 1600 shown in FIG. 16.

In the description above, a CHO has been exemplary mentioned as aconditional mobility for the sake of convenience. The present disclosurecan also be applied to other forms of conditional mobility, such asconditional PSCell change/addition without loss of generality.Furthermore, the present disclosure can also be applied to normalmobility instead of conditional mobility.

The present disclosure can have various advantageous effects.

For example, the present disclosure resolves to prevent unnecessaryinvalid handling when a mobility condition for a candidate target cellis met without the corresponding target cell configuration aftersuccessful mobility such as CHO. Also, the UE doesn't have to performRRC re-establishment procedure which cause data interruption by invalidcase handling.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod. Other implementations are within the scope of the followingclaims.

What is claimed is:
 1. A method performed by a wireless devicecomprising: identifying a first cell which satisfies a mobilitycondition for the first cell included in a conditional mobility commandof the first cell; and based on a determination that a target cellconfiguration for the first cell is unavailable, transmitting a reportcomprising information for an unavailability of the target cellconfiguration for the first cell.
 2. The method of claim 1, furthercomprising: receiving conditional mobility commands of target cells,wherein each of the conditional mobility commands is related to each ofthe target cells, and the conditional mobility commands comprise aconditional mobility command of a second cell among the target cells;and performing a mobility to the second cell by applying a target cellconfiguration for the second cell in the conditional mobility command ofthe second cell, before identifying the first cell and transmitting thereport, wherein the identifying the first cell and the transmitting thereport are performed while the wireless device is being served by thesecond cell as a serving cell.
 3. The method of claim 2, wherein thetransmitting the report comprises: after performing the mobility to thesecond cell, transmitting the report based on a determination that thefirst cell satisfies the mobility condition for the first cell, and thetarget cell configuration for the first cell is unavailable.
 4. Themethod of claim 2, wherein the performing the mobility to the secondcell comprises: based on identifying that a mobility condition for thesecond cell is satisfied, performing the mobility to the second cell. 5.The method of claim 4, wherein the mobility condition for the secondcell becomes the mobility condition for the first cell according to ameasurement identity swapping after performing the mobility from thefirst cell to the second cell, and wherein the target cell configurationfor the first cell is determined as being unavailable based on that themobility is performed from the first cell to the second cell.
 6. Themethod of claim 2, wherein the conditional mobility commands comprisethe conditional mobility command of the first cell among the targetcells, and wherein the performing the mobility to the second cellcomprises: based on identifying that the mobility condition for thefirst cell is satisfied, initiating the mobility to the first cell andstarting a timer; after an expiry of the timer, removing the target cellconfiguration for the first cell and performing a cell selection; andbased on identifying that a cell to which the cell selection isperformed is identical to the second cell, performing the mobility tothe second cell.
 7. The method of claim 6, wherein the target cellconfiguration for the first cell is determined as being unavailablebased on that the target cell configuration for the first cell has beenremoved.
 8. The method of claim 1, further comprising: based on adetermination that the target cell configuration for the first cell isunavailable, performing a mobility to the first cell by applying astored target cell configuration for the first cell, wherein the storedtarget cell configuration for the first cell is not obtained by theconditional mobility command of the first cell.
 9. The method of claim1, wherein the report is transmitted via a measurement report comprisingmeasurement results on one or more cells.
 10. The method of claim 1,wherein the wireless device is in communication with at least one of auser equipment, a network, and/or autonomous vehicles other than thewireless device.
 11. A wireless device in a wireless communicationsystem comprising: a transceiver; a memory; and at least one processoroperatively coupled to the transceiver and the memory, and configuredto: identify a first cell which satisfies a mobility condition for thefirst cell included in a conditional mobility command of the first cell,and based on a determination that a target cell configuration for thefirst cell is unavailable, control the transceiver to transmit a reportcomprising information for an unavailability of the target cellconfiguration for the first cell.
 12. The wireless device of claim 11,wherein the at least one processor is further configured to: control thetransceiver to receive conditional mobility commands of target cells,wherein each of the conditional mobility commands is related to each ofthe target cells, and the conditional mobility commands comprise aconditional mobility command of a second cell among the target cells,and perform a mobility to the second cell by applying a target cellconfiguration for the second cell in the conditional mobility command ofthe second cell, before identifying the first cell and transmitting thereport, wherein the identifying the first cell and the transmitting thereport are performed while the wireless device is being served by thesecond cell as a serving cell.
 13. The wireless device of claim 12,wherein a mobility condition for the second cell becomes the mobilitycondition for the first cell according to a measurement identityswapping after performing the mobility from the first cell to the secondcell, and wherein the target cell configuration for the first cell isdetermined as being unavailable based on that the mobility is performedfrom the first cell to the second cell.
 14. The wireless device of claim12, wherein the conditional mobility commands comprise the conditionalmobility command of the first cell among the target cells, and whereinthe at least one processor is further configured to: based onidentifying that the mobility condition for the first cell is satisfied,initiate the mobility to the first cell and starting a timer, after anexpiry of the timer, remove the target cell configuration for the firstcell and perform a cell selection, and based on identifying that a cellto which the cell selection is performed is identical to the secondcell, perform the mobility to the second cell, wherein the target cellconfiguration for the first cell is determined as being unavailablebased on that the target cell configuration for the first cell has beenremoved.
 15. A computer-readable medium having recorded thereon aprogram for performing each step of a method on a computer, the methodcomprising: identifying a first cell which satisfies a mobilitycondition for the first cell included in a conditional mobility commandof the first cell; and based on a determination that a target cellconfiguration for the first cell is unavailable, transmitting a reportcomprising information for an unavailability of the target cellconfiguration for the first cell.